If we react for every price fluctuation on cryptocurrency market finally we will not get anything in our wallet so I advise you to hold your Bitcoins for long term profitable goals.
If you want to react for the fluctuation you need to be a trader or trader mindset while you deal such situation. Investment on BTC is like gold and you don't need to worry for small fluctuations.
Reacting to price fluctuation is very common among the users, but for the same just holding isn't gonna give an earning same as trading between the difference out of the fluctuations. What's been advised is wrong, because with crypto market we need to do something continuously only then it is possible to learn and earn something.
Holding is much preferred by users who doesn't wish to risk themselves, and they're satisfied with what's been got out of the long term holding between the days of buying and selling.